Charged particle beam apparatuses have many functions, in a plurality of industrial fields, including, but not limited to, critical dimensioning of semiconductor devices during manufacturing, defect review of semiconductor devices during manufacturing, inspection of semiconductor devices during manufacturing, exposure systems for lithography, detecting devices and testing systems. Thus, there is a high demand for structuring, testing and inspecting specimens or samples within the micrometer and nanometer scale.
Micrometer and nanometer scale process control, inspection or structuring is often done with charged particle beams, e.g. electron beams, which are generated and focused in charged particle beam devices, such as electron microscopes or electron beam pattern generators. Charged particle beams offer superior spatial resolution compared to, e.g. photon beams due to their short wavelengths.
In recent years, inspection and/or imaging of 3D structures or structures having large aspect ratios (such as large ratios of depth to opening width) becomes increasingly desired. Devices like 3D FinFETs and 3D NANDs have structures with large aspect ratios which are difficult to image in scanning electron microscopes (SEMs) using the secondary electrons (SE). SEs can hardly escape from the structures having high aspect ratios and cannot be detected with reasonable signal to noise ratio. In particular, the bottom critical dimension (CD)-measurement of high aspect ratio trenches and contact holes is a challenge. Image modes which use backscattered electrons (BSE) are used for increasing the quality of imaging and/or inspection, especially in the semiconductor industry. However, in known systems, the BSE detection has an undesired impact on the primary beam performance (e.g. the resolution).
In view of the above, it is an object of embodiments described herein to provide a charged particle beam device, a proxy electrode, and a method for inspecting and/or imaging a sample that overcome at least some of the problems in the art.